Safety-stop for elevators.



I N.- O. L'INDSTROM.

SAFETY STOP FOR ELEVATORS APPLICATION FILED SEPT. 9. 1915.

Patented Mar. 5, 1918.

3 SHEETSSHEET I N. O. LINDS'IROM.

SAFETY STOP FOR ELEVATORS.

APPLICATION men SEPT. 9 1915'.

Patented Mar. 5,1918.

3 SHEETS-SHEET 2.

N. O. UNDSTROM.

SAFETY STOP FOR ELEVATORS.

APPLICATION FILED SEPT. 9.1915.

avwewhoz Patented Mar. 5, 1918.

Unrrnn srairns ran NILS O. LINDSTRGIVI, OF NUTLEY, NEW JERSEY, ASSIGNGRT ALO'NZO B. SEE, OF BROOKLYN, NEW YORK.

SAFETY-STOP FOR ELEVATORS.

Application filed September 9, 1915.

To all whom it may concern:

Be it known that I, NrLs O. LINDSTROM, a citizen of the United States,residing at Nutley, in the county of Essex and State of New Jersey, haveinvented certain new and useful Improvements in Safety-Stops forElevators, of which the following is a full, clear, and exactspecification.

This invention relates to safety stops for elevators 0f the class inwhich an abnormal invention are pointed out in the followingspecification and in the appended claims.

In the accompanying drawings Figure 1 is an elevation, partly insection, of the lower portion of an elevator car, and of my safetyappliance, the solenoid being shown conventionally. Fig. 2 is a planview, partly in section, of one of the guide rails, one of the grippingjaws and mechanism for operating the same. Fig. 3 is a sectional view,on the line Y Y of Fig. 2. Fig. 4 is a sectional view on the line X X ofFig. 3. Fig. 5 is a detail elevation of a modification of the means forreopening the gripping jaws and rewinding the cable 15 on the drum 14.Fig. 6 is a section on the line V V of Fig. 5.

Similar characters of reference refer to similar parts throughout theaccompanying drawings, in which 1 is the lower portion of an elevatorcar, 2 the guide rails in the elevator shaft, 3 gripping jaws hinged at4 and held in the open position by springs 5. The inner portions of thejaws are provided with anti-friction rollers 6, and between the jaws arewedges 7, retained in position in guides 8. Each of these wedges isprovided with a tail piece 9, the inner end 10 of one of which isprovided with a right screw-thread and the inner end 11 of the otherwith a left screw-thread. Each of the tail pieces is provided with across head 12, sliding on guides 13, which serves to prevent therotation of the wedge. Mounted underneath the bottom of the car is adrum 14 which is interiorly provided with right and left screw threads,

Specification of Letters Patent.

Patented Mar. 55,1918. eria1No.49,671.

to receive the screw-threadedends of the tail pieces of the wedges. Oneend of a cable or cord 15 is secured to the drum 14 at 16. The cord 15is wrapped or wound about the drum and is then passed around the sheaves17 and between the sheaves 18, all of which sheaves are mounted on thecar. This end of the cord or cable is then secured at 19 to an endlesscord or cable 20, which passes over a stationary sheave 21, mounted nearthe top of the elevator shaft and around a weighted sheave 22, locatednear the bottom of the elevator shaft. Mounted in operative relation tothe sheave 21 is a governor 37. 'Mounted in operative position withreference to the cable is gripping mechanism, consisting of stationarymembers 23 and levers 24 pivoted at 25, and connected at their upperends to the core pieces 26 of the solenoid 27, by which they are heldout of engagement with the cable 20 against the tension of the springs28, whenever the solenoid is energized. In the circuit CC,-designed tosupply electric current to energize the solenoid 27 is a switch 29,which is held in closed position by the latch 30. In the same circuitand mounted in the car within reach of the operator is an emergencyswitch 31, adapted to be manually operated by the operator of the car.The governor 37 is provided at its upper end with a guide post 32, uponwhich is mounted a sleeve 33, adapted to be moved up and down as thespeed of the governor increases or diminishes. In operative relation tosaid sleeve is a plunger 34, which is adapted to trip the latch when thegovernor 22 is rotated at a predetermined speed. Mounted on the drum 14is a Worm gear 35, which is adapted to be operated by a removable wormshaft 36, inserted into the guideway 28, so

as to open the gripping jaws and replace I the mechanism in theinoperative position shown in Fig. 1. I

In order to close the switch 29, I have provided a solenoid 40. Thecircuit t. t. which is designed to supply current for the pur- 7 pose ofenergizing the solenoid '40, is normally open, but may be closed byclosing the button switch 41, carried by the elevator.

In the modification shown in Figs. 5 and. 6, the guideway 38 is hingedat 42, so that the worm shaft 36 may be swung out of and into engagementwith the worm gear 35. When in engagement it is locked in position bythe latch 43, hinged at 4A. The core piece 45 of the solenoid 46 issecured to the latch 47. The latch is also provided with an arm 48, inthe end of which is mounted a friction roller 19. When the solenoid isactuated, the latch 43 will be lifted out of engagement with the catchon the guideway and carrying with it the arm 48 which, as it rises, willforce back the guideway 38 and carry with it the worm shaft 36, untilthe worm shaft 36 is out of engagement with the worm gear 35, nor maythe worm shaft 36 be again swung into engagement with the gear 35, untilthe solenoid 46 has been deenergi'zed.

An electric "circuit ER is designed to sup ply electric current for thepurpose of energ ing the solenoid 46. The circuit is closed by a switch51, which is carried by the switch 29, the construction being such thatwhen the switch 50 is closed the switch 29 is open and when the switch50 is open the switch 29 is closed.

T he operation of my device is as follows:

Normally the cable 20 is free to run over the sheaves 21 and 22, andwhen so running the load on the cable 15 is insufficient to operate thesafety device. lVhen, however, the speed of the car and thecorresponding speed of the cable 20 and the governor 37 is increased tothe speed at which the latch 30 has been adjusted, the governor 37 willtrip the latch 30. and open the switch 29, thereby cutting off thecurrent from the solenoid 27, which permits the springs 28 to cause thelevers 24 to grip the cable 20 and hold it stationary. The movement ofthe car then unwinds the cable 15 on the drum 14:, causing the drum torotate and draw the wedges between the inner jaws of the mechanism,thereby causing the gripping jaws to gradually and gently grip the guiderails until the car is brought to a stop. It isapparent that thedistance which the car is permitted to move after the safety applianceis thrown into operation is dependent upon the pitch of the threads onthe tail pieces 9 and the diameter of the drum. The switch 31 isprovided so that the operator of the car may manually break the solenoidcircuit and throw the stop mechanism into operation whenever anemergency arises, without waiting for the car to attain an undue speed.lVhen the car has been brought to rest, the gripping jaws may be openedand the mechanism for operating them reset by inserting the worm shaft86 into the guideway 38 and rotating it until it seats in the base ofsaid guideway. Further rotation of the worm shaft will rotate the drum1%, rewind the cable 15, force back the wedges 7, and permit the springs5 to open the gripping jaws. The rotation of the worm shaft is thencontinued until it may be Withdrawn without closing the gripping jaws.

The circuit 6. t. may then be closed by means of the button switch 41and the solenoid l0 energized, causing it to close the switch 29.

TV he "e the modification shown in Figs. 5 and 6 is employed, wheneverthe circuit energizing the solenoid 21 is broken and the safety stopdevice is in operation, the switch 50 is closed, the solenoid 46actuated, the latch 43 lifted out of engagement with the catch 50, andthe worm shaft 36 forced and held by the arm 48 out of engagement withthe worm gear 35, so that the operator cannot release the gripping jaws3 from the guide rail 2 until the switch 29 has been closed and thewhole safety stop mechanism thereby reset so that it will again be rendered operative if the car should attain an undue speed after thegripping jaws 3 have been released.

Having described my invention, I claim- 1. A safety stop for elevators,comprising brake mechanism having gripping members and automatic meansfor operating the same including a trip, means for releasing saidgripping members and automatic means for preventing the operation of themeans for releasing said gripping members until the trip has been reset.

A safety stop for elevators, comprising brake mechanism and automaticmeans for operating the same, manually controlled means for releasingthe brake mechanism and automatic means for preventing the operation ofthe means for releasing the brake mechanism until the automatic meansfor operating the brake mechanism has been adjusted, so that it is againoperative.

3. A safety stop for elevators 'comprising gripping j aws, automaticmeans for closing said gripping jaws and manual means carried by the carfor opening said gripping jaws and electric means for resetting saidautomatic mechanism.

Signed at New York city in the county of New York and State New York,this 31 day 'of August, 1915.

NILS O. LINDSTROM.

Witnesses:

CATHARINE M. BYRNE, BENJAMIN T. ABRAMS.

Copies 01 this patent may be obtained for five cents each. by addressingthe Commissioner 01' Patents,

Washington, D. G.

